Electrical apparatus



March 27, 1928.

J. M. LALER ELECTRI CAL APPARATUS Filed March 23, 1925 INVENTOR Jea/wf/M mele Patented Mar. 27, 1928.

UNITED STATES PATENT OFFECE...

JEROME M. LALER, OF BURLINGAME, CALIFORNIA., ASSIGNOR TO CEAS. CORY &SON,

' INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NW YORK.

ELECTRICAL APPARATUS.

Application led March 23, 1925. Serial No. l17,680.

This invention is an improvement in electrical apparatus, and moreparticularly in terminal boxes or receptacles and connecting plugs forcooperating therewith.

For convenience in tapping electrical circuits it is usual to interposein the circuit ter.- minal boxes or receptacles in selected locations,the apparatus to be connected having connecting plugs, which carrycircuit terminals designed to cooperate with those of the box, toelectrically connect the apparatus with the source of current supply.

ln marine work especially, the terminal box or casing should be fluidtight, and this condition should obtain when the plugs are removed, aswell as when they are in place, in order that the connections beprotected, and water be excluded, at all times. Hence mechanism toprovide a fluid tight joint between the plug and the receptacle isnecessary, as well as other mechanism to close the opening or socketthrough. which the plug engages, when the plug is withdrawn.Furthermore, such mechanism should not only be fool-proof, so far aspossible, but should be proof against inadvertence resulting in partialor incomplete insertion of the plu In adition to such general objects asthe providing of a construction of box or casing which will befluid-tight when the plug is in place as well as when the plug isremoved, and the provision of a mechanism for closing the opening orsocket of the casing which is automatic in its action and normally urgedto closing position, so that when the plug is removed the opening isautomatically closed without the necessity of attention by the operatoror attendant, one of the prime objects of my invention is the provisionof a plug and socket of such interrelated construction that thefunctioning of the plug as a circuit-maker is dependent upon theestablishment of a water-tight connection between the plug and the box.

Another object is the provision of a simple and inexpensive constructionof plug and casing so constructed and arranged that the plug in additionto its connecting function also serves as a switch, for engaging and ldisengaging the circuit terminals.

To the accomplishment of the foregoing and such other objects as mayhereinafter appear, the invention consists in the construction and novelcombination of parts fully described hereinafter, illustrated in the'accompanying drawings, and pointed out 1n the claims appended hereto,it being understood that various changes in the form, p1.'o1')ortion,size and minor details of construction, Within the scope of the claims,may be resorted to without departing from the spirit of the invention.

Fig. 1 is a longitudinal'section of the improved casing and plug, withthe plug in position to function as a connector.

Figs. 2 and 3 are sections on the lines 2-2 and 3-3, of Fig. 1.

ln the present embodiment of the invention, a receptacle or casing isprovided including a body 1, of suitable shape and size, and adetachable cover 2, held to the casing body bylmeans of screws 3 or thelike. A gasketA' is arranged between the cover and theA body, for makinga water tight joint, and the cover has a transversely extending socketor nipple 5 providing an inlet opening for the plug to be described.

Blocks 6 of insulating material are secured to opposite side walls ofthe casing, and contact elements 7 in the form of strips of conductingmaterial are supported by the blocks, being'conneeted thereto by screwbolts 8 as shown. The contact elements extend on opposite sides of thesocket 5, and

the free ends are offset inwardly toward each other as shown.

At the opposite end'of each contact element 7 from the inwardlyoiisetportion a lug 8 extends inwardly toward the middle of the casing,and each of these lugs has a screw 9 threadedly engaged therewith, forconnection with the leads 10 of the electrical circuit which is tosupplycurrent to the apparatus engaged with the plug.

The casing may be tapped at any suitable point, to provide an inletopening for the circuit leads, preferably on the ends, which arereinforced as indicated at 11, to provide a sufficient hold for thethreaded end of a conduit 12. The circuit leads 13 are carried by acable which passes through the conduit as shown in Fig. 1.

The plug comprises a substantially cylindrical body 14 having its outerend reduced. The cable 15 carrying the outlet leads 16 passes through abushing 17, preferably of soft rubber, and a cap 18 is threaded onto thereduced end of the body 14, engaging the cap', and acting to expand saidbushing when the cap is tightened thereby to effectually seal the spacebetween cable and body.

As Ishown in Fig. l. the bushing 17 tapers in both directions. and theouter end of the reduced portion ot the body 14 is roamed to tit one endot' the bushing. rlhe bushing extends beyond the end ot the body, andthe cap which hasl an opening 19 for the cable, is arranged to compressthe bushing against the reamed portion ot' the body.

The body of the plug is of a size to [it easily within the nipple orsocket 5, and it i connected to the socket, in a water ti jht manner, byinea-ns of a collar 20 having threaded engagement with the socket, andengaging an annular shoulder or ledge 21 on the body. A gasket orpacking 22 is arranged between t-he collar and the end of the socket,against which the rib 21 may be forced by the collar to `torni a sealand a water tight connection at this point.

A block 23 of insulating material is held centrally of the socket, bymeans of a cross pin 2t, and contact elements 25 are secured to thelower end otl the block, the said block extending beyond the inner endof the plug body, and beyond the inner end of the socket when the plugis in place.

As shown more particularly in Figs. 2 and the block 23 at its lower endis provided with a cross head 26, and the contact elements 25 areextended around the ends of the head, so that each member laps upon twosides and one end of the cross head. The length of the cross head,including the laps ping contact elements is greater than the normaldistance between the Contact elements 7, while the width of the head,including the contact elements 25, is considerably less than lnichdistance.

Since. the contact elements 7 are equally .spaced from the axis of theplug, it will be evident that when the plug is introduced with the head26 extending longitudinally ol the casing, there will be no cooperatingengagement between the contact elements 25 and 7 The plug must be movedangularly a distance of 90 degrees, to bring the head transverse to thecasing before such cooperative engagement obtains. Means is provided inconnection with the socket for preventing introduction or removal of theplug` except when the contact elements 25 are out of cooperativerelation with the elements 7. Said means is an opening 27 at the innerend of the socket, of rectangular shape, and of a size approximatelythat of the head plus the strips 25. The opening 2T is ot a size, andshaped to permit the passage ot the head, when it extends longitudinalto the casing, and it cannot pass into or out of the casing in any otherposition.

This collar 20 and its restricted movement on the body portion of 'cheplug constitute nceamil an important feature ol my invention. Byreference to ltigs. 1 and 3, it will be noticed that the relativemovement of this collar 20 is limited to the distance between the rib 21and the lower end of the sleeve portion ot the collar 28. llt. will benoticed that the Space through which said collar r2O has movement. onthe body port-ion of the plug is substantially less than the distancethrough which said collar must be threaded on the upper end of thesocket, in order to permit oi a clearance between the crosshead 26 andthe lower end ot' the socket.

It will be apparent, therefore, that when the plug is initially insertedin the socket, the thread at the lower end of the collar 20 will envagethe thread at the upper end of the soc {et and check the operation ofthe insertion of the plug prior to clearance between the cross-head 26and the lower end of the socket. Thus, in order to effect the desiredelectrical connection, it is necessary to screw said collar 20 down uponthe threaded portion of said socket a sufficient distance to effect thisclearance, and in so screwing said collar on said socket, a wat-ertightconnection is established and must be established before the device as awhole will function.

The construction enables the plug to serve also as a switch, forconnecting the branch circuit leads 16 with the supply circuit leads 13.Inserting the plug, and moving it over an angular distance of 90 degreeswill make the desired connection, and the connection must be made withthe box before the plug is used. For convenience in turning the plug, acollar 28 is secured to the plug body by means of the screw 29 or thelike, the collar as well as the collar 20, and the cap 18, havingknurled edges for convenience in manipulation.

In order to provide a seal and water tight closure for the inner end ofthe socket 5 when the plug is removed, a plate 30 is mounted at theinner end of the socket. The said plate is faced with a layer of packingmaterial 31, and is slidably mounted at its ends on guide rods 32, whichare threaded into nipples 33 uprising fromthe bottom of the casing body.Each rod is encircled by a spring 34 between the plate and the nipple,the springs normally urging the plate upward against the inner end ofthe nipple or socket to seal the same. Stops 35 in the form of cotterpins are provided at the tops of the rods, to limit the upward movementof the plate, and rubber washers 36 encircle the rods above the packingplate which is of rubber or like material.

The plu is rotatable in the socket, in order that t e connection may bemade by angular movement of the plug through an are of 90 degrees, andin order to center the plug when itis inserted, the lower end of1,eea,711

the plug 23 has an axial recess 37, which is designed for engagement bya centering pin 38 in connection with the plate 30. This pin may be arivet as shown, passing through the plate 30 and the backing 31, andassisting to hold the backing to the plate.

A cover is provided for the socket when the box is not in use, that iswhen the plug is removed. The cover is in the form of a cap 39 threadedto engage the outer end of the socket and cap the same. The cap has aswinging connection with the cover 2 of the box, an arm 40 is pivoted tothe box at 41, at one end of the arm, and to the cap at the other end,as indicated at 42. The arm is of a length such thatthe cap may be swunginto axial register with the socket, and since the cap is pivotallyconnected with the arm, it may be turned to engage the socket or torelease the same. The pivotal connections 41 and 42 are loose withrespect to the arm 40 to permit the necessary movement of the cap inengaging and releasing the socket.

In the use of the improved box and plug, when it is desired to makeconnection at any selected box, the cap 39 is removed, and the plug isinserted. The inner end of the plug 23 engages and depresses thenormally operative closure 30-31 for the socket, the said closure movingdown between the terminals 7. The pin 38 centers the plug, and after theplug has been inserted, the collar 20 is turned down to make a watertight connection. When so connected, angular movement of the plugthrough an are of 90 degrees will connect the branch leads 16 with thesupply leads 13. The plug must be inserted with the head 26 extendinglongitudinally of the box, and it must be securely connected to\ the boxbefore it can function perfectly as a switch, or as a connector. Unlessit is connected to the box, the springs 35 willpush it out of engagingposition. As soon as the plug is released and Withdrawn, the closure30-31 moves against the inner end of the socket sealing the same with aWater tight Seal.

I claim:

1. Apparatus of the class described, including a terminal box and aconnecting plug, the plug having a cross head for connecting with theterminals, and the box and opening shaped to tit the cross head and withits axis at an angle to the position assumed by the plug when makingconnection, the box having a threaded nipple encircling the openingthrough which nipple the cross head must pass to enter the opening, anda collar on the plug for threadedly engaging the nipple to make a fluidtight connection, said collar abutting the end of the nipple before thecross head clears the opening and retaining the cross head in theopening until threaded down upon the nipple.

2. Apparatus of the class described, in-

cluding a terminal box and a connecting,

plug, the plug having a cross head for connecting with the terminals,and the box and opening shaped to tit the cross head and with its axisat an angle to the position assumed by the plug when making connection,the box having a threaded nipple encircling the opening through whichnipple the cross head must pass to enter the opening, a collar on theplug for threadedly engaging the nipple to make a fluid tightconnection, said collar abutting the end of the nipple before the crosshead clears the opening and retaining tlie cross head in the openinguntil threaded down upon the nipple, and a normally operative fluidtight closure for the opening, opened and held opened by the 1nsertionof the plug.

Signed at Burlingame, in the county of San Mateo and State ofCalifornia,this 11th day of March A. D. 1925.

JEROME M. LADER.

